Portable mixing machines are often used to mix liquids in drums and other shipping containers after storage and prior to the transfer or use of the contents, in order to assure a homogeneous mixture. Some mixing machines use a propeller type mixer arranged in a preferred geometrical relationship in a relatively tall, narrow cylindrical tank in order to achieve optimum mixing efficiency. In the preferred geometric relationship, the propeller is placed at a point near the bottom of the tank with the axis of the propeller shaft following a line from about the top circumferential edge of the tank downward at a vertical angle away from the tank wall and at a horizontal angle to a selected side of the center of the tank as viewed from above.
The contents of such drums often contain a high percentage of solids which are subject to settling and/or are viscous in nature, which can require that a motor of substantial horsepower be used to mix the contents. Such a motor equipped with a propeller, shaft, and mounting device can easily weigh in excess of 30 pounds, which can be difficult for the average person to maneuver and install with safety.
Some commercially available portable mixing machines utilize a clamp type mount to secure the mixer to the upper rim of a drum or tank. This will ordinarily allow the propeller to be positioned for best mixing if the mount is adjusted properly. However, such mixers are difficult to install due to weight considerations and the fact that the machine must be held in position with one hand while the operator secures the mounting clamp with his other hand.
Another type of portable mixer utilizes a mount that screws into the threaded opening provided in the top of drums. For metal drums the standard opening is a 2"female National Pipe Threat (NPT). The standard location for this opening is as near as practical to the edge. Mixers of this type are relatively easy to install on a drum as both hands may be used to guide the male thread into the female thread. However, such machines have disadvantages. The propeller cannot be positioned for optimum mixing because the impeller shaft enters the opening on the axis of the threaded opening. Any appreciable deviation from a coaxial arrangement may result in the propeller contacting the side of the drum as the mount is threaded into the opening. Also, the cord must be managed as the motor is rotated during the threading process.
Accordingly, one object of this invention is to provide new and improved mixing apparatus for mixing liquids in a drum or other container which positions a rotating propeller for optimum mixing efficiency.
Another object is to provide new and improved portable drum mixing apparatus which is easily installed in a positive manner.
Yet another object is to provide new and improved portable drum mixing apparatus which can be secured to a drum or the like in a positive manner, without twisting or tangling the power cord.